linux-kernel - Re: [PATCH 0/4] x86_64: Optimize percpu accesses

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Date:	Fri, 25 Jul 2008 17:30:57 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Mike Travis <travis@....com>
CC:	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Hugh Dickins <hugh@...itas.com>,
	Jack Steiner <steiner@....com>,
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/4] x86_64: Optimize percpu accesses

Mike Travis wrote:
> Yes, you're right, I wrote that quickly without really reading it back.
> My point is that now that x86_read_percpu() and x86_write_percpu() do
> evaluate to a single instruction (by definition atomic), then it doesn't
> need to be surrounded by the preempt_disable()/preempt_enable() calls.
>   

Yep, correct.

> It appears as if I'm implying that's the case for get/put_cpu_var().
>   

Right.

    J
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